The present invention relates to an annular outer joint part for a constant velocity joint.
The invention relates to an annular outer joint part for a constant velocity joint, comprising a first end face and a second end face. In the inner wall of the outer joint part, there are arranged first outer grooves which start from the first end face and extend to the second end face, with the first groove base approaching the longitudinal axis toward the second end face, and having second outer grooves which start from the second end face and extend to the first end face, with the second groove base approaching the longitudinal axis toward the first end face, wherein the first outer grooves and the second outer grooves alternate on the circumference of the inner wall.
U.S. Pat. No. 5,221,233 describes a constant velocity joint wherein the annular outer joint part, in its inner wall, comprises first and second outer grooves which start from different end faces and alternate on the circumference of the inner wall.
Opposite the first and second outer grooves, there are arranged first and second inner grooves of an inner part which is positioned in the outer joint part, wherein the first inner grooves start from the first end face from which the first outer grooves also start and wherein the groove base of the first inner grooves extends from the first end face to the second end face with an increasing distance from the longitudinal axis, whereas the groove base of the first outer grooves approaches the longitudinal axis from the first end face to the second end face. Accordingly, the second inner grooves and the second outer grooves start and extend from the second end face.
Between the outer joint part and the inner joint part there is arranged a cage which guides balls engaging opposed inner and outer grooves. To keep the depth of the first outer grooves and the second outer grooves as constant as possible, the webs arranged on the circumference of the inner wall between each two outer grooves are divided, so that there are obtained two web portions which, together, form parts of a hollow spherical inner face in the outer part, but the partial faces are axially and circumferentially offset at the inner wall. The tool required for such an outer joint part is complicated. Furthermore, by applying a force in the radial direction, the outer joint part is divided into two individual annular segments. These are accommodated in a bore of a bell after the inner part has been assembled with the cage and the balls. The bell supports the outer part in the radial direction. To achieve a rotationally fast connection, one of the end faces of the outer joint part has been provided with recesses. After the unit has been inserted, the wall of the bell is deformed in such a way that material in the region of the recesses of the outer joint part is displaced. The bell itself serves to establish a connection with a driving or driven part.
U.S. Pat. No. 6,261,184 describes a constant velocity joint with an annular outer part which is produced from plate metal and, especially, is composed of segments and which include first outer grooves and second outer grooves. It is formed of plate metal strips. The annular segments are received in a receiving part which is formed of plate metal and includes recesses in which the recesses of the segments forming the outer running grooves, are received. The joint produced from plate metal is particularly suitable for applications wherein the torque to be transmitted is relatively small and wherein it is important that there is no play. The elasticity of the plate metal makes it possible to achieve close tolerances because a limited elasticity does not adversely affect the guidance of the cage.
It would be desirable to provide an outer joint part for a constant velocity joint having a simplified construction.
The present invention provides an outer joint part for a constant velocity joint, including first and second outer grooves whose depth in the region between the first and the second end face is substantially constant, with the production process having been simplified.
In accordance with the invention, an annular outer joint part for a constant velocity joint is provided. The outer joint part includes a first longitudinal axis, a first end face and a second end face. First outer grooves are arranged in the inner wall. The first outer grooves start from the first end face and extend to the second end face, with the first groove base approaching the longitudinal axis toward the second end face. Second outer grooves start from the second end face and extend to the first end face, with the second groove base approaching the longitudinal axis toward the first end face. The first outer grooves and the second outer groove alternate on the circumference of the inner wall. The outer joint part also includes an outer face from which there project first webs and second webs which extend parallel to the longitudinal axis and alternate on the circumference. The first webs are arranged so as to correspond to the first outer grooves. Thus, they start from the first end face, andxe2x80x94when viewed in first sectional planes which extend through the longitudinal axis and through the first groove base of the associated first outer groovesxe2x80x94end in front of the second end face. The second webs are arranged so as to correspond to the second outer grooves. Thus, they start from the second end face andxe2x80x94when viewed in second sectional planes which extend through the longitudinal axis and through the second groove base of the second outer groovesxe2x80x94end in front of the first end face.
An advantage of the present invention is that over the important operating range (range of angle of articulation) of a constant velocity joint in which such an outer joint part is used, it is possible to achieve an approximately constant depth of the outer grooves, so that the load applied to the part of the outer joint part is substantially constant and the degree to which the torque transmitting ability is dependent on the articulation angle is more advantageous. A further substantial advantage is that no special measures are required at the outer joint part for torque transmitting purposes, i.e. the torque connection between the outer joint part and a receiving part. The webs can at the same time be used for torque transmitting purposes. A special advantage is due to the fact that the wall thickness of the outer joint part in the region between the two end faces and in the circumferential direction does not comprise any substantial steps, so that, during the required heat treatment, i.e. hardening, the risk of distortion is minimized.
In particular, this advantage results if the outer faces of the first webs in the first sectional planes and the second webs in the second sectional planes, while starting from the respective end faces from which they start, follow the groove base of the respective associated outer groove at identical distances and end in the outer face.
A further embodiment is advantageous with respect to production if each web is delimited by an outer face which, in any cross-section intersecting the longitudinal axis at a right angle, extends in a circular arch around the longitudinal axis, and by two planar flanks which extend parallel to the associated first and second sectional plane. The two planar flanks advantageously affect the transmission of torque.
The remaining part of the outer face, in its region which is free of webs, is provided in the form of a cylindrical face around the longitudinal axis. It can be used for centering the outer joint part in a receiving part.
The outer faces of all webs, together, form part of an imaginary cylindrical face around the longitudinal axis. In order to increase the production accuracy when using non-chip forming deformation, between each two first outer grooves and second outer grooves following one another on the circumference of the inner wall, there is provided a groove which extends parallel to the longitudinal axis. During calibration, for example, displaced material can escape into this groove.
Furthermore, it is possible to divide the outer joint part along a groove through a slot in order to facilitate the assembly of a constant velocity joint which includes the outer joint part.
Non-chip producing deformation is also facilitated if the end face includes a first region in which the end face is arranged on a plane which intersects the longitudinal axis at a right angle and, in the direction pointing towards the longitudinal axis, changes into a second region which is arranged on a conical face, the conical face being tapered towards the longitudinal axis.
According to a further embodiment of the invention, there are provided inner webs which are arranged in the circumferential direction between two outer grooves following one another and which are divided into first inner web portions and second inner web portions, which outer joint part is interrupted by one single separating join or groove which is introduced after the final dimensions have been produced by machining and subsequent hardening and extends between the inner web portions of an inner web.
The advantage of this design is that the elasticity of the outer joint part can be used for mounting a thicker cage which is suitable for larger articulation angles. Mounting is simplified because the outer joint part remains a complete component. In this way it is possible to prevent parts from being moved together which do not belong together. The operation of moving parts together is eliminated.
In one embodiment, the separating join is provided in the form of a slot which is produced by a chip-forming operation. The outer joint part is centered in a receiving part in such a way that the slot is maintained in its production size. In particular, this can be achieved if the outer joint part comprises webs and if the receiving part is provided with matching recesses which center the outer joint part. In this way it is ensured that no displacement can take place in the circumferential direction of the outer joint part, i.e. the outer joint part cannot be bent open or pressed together, which would have adverse effects on the play conditions of the constant velocity joint. For example, the outer joint part in the form of a round blank can be given its final dimensions by deep-drawing or sizing. Separation takes place in the hard condition, i.e. after the outer joint part has been hardened, for example by using a separating disc.
Alternatively, the outer joint part can be produced from a through-hardening material, and the separating join can be a brittle fracture. Together with the separating join, the outer joint part is subjected to a heat treatment in the sense of tempering in order to achieve the necessary toughness.
An assembly having an inventive outer joint part and a receiving part in which it is received is also provided. The receiving part includes a receiving bore in which the outer face of the outer joint part is received in a centered way, as well as receiving grooves in which the webs are received. The receiving part can be provided in the form of a wheel hub for a driven wheel of a motor vehicle.
For sealing purposes towards the outer joint part, the receiving part is closed by a cap and at least part of the remaining space is filled with a filler material.
Other advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.